south korea's president will meet with president obama. the white house announced the may 7th visit yesterday. including how to counter north kor korean threat. >> happy birthday to pope benedict. the former pontiff is the oldest and resigned citing a back of strength due to his age. he served for almost 8 years. >> series of earthquakes have rattled parts of central oklahoma this morning. four small quakes have hit and are centered northeast of oklahoma city and range in magnitude of 4.8 and 2.3. so far no reports of injuries or damage. >> 6:20 is our time now. investigators are working together to figure out who is responsible for the terror attack in boston. nbc's stephanie himinez is live where the blast happened. good morning. good morning to you. we are about five blocks away from where those bombs wept off yesterday. we see barricades as so ficials try to see what happened xwres ter day. people were setting up for the marathon. but that atmosphere quickly changed yesterday at 3:00 p.m. as ruppers were crossing that finish line and t